Apparatus for sub-zero treatment of metals



I5 Sheets-Sheet l J. K. HEYL ET AL k INVEA/ogs. BY

im ATTo/eA/Eys.

April 17, 1956 Filed July 29. 1952 INVENTORS.

J. K. HEYL ET AL 3 Sheets-Sheet 2 @01%,l/Mwufw ATTONE 5.

April 17, 1956 APPARATUS FOR SUB-ZERO TREATMENT OF METALS Filed July 29, 1952 April 17, 1956 J. K. HEYL |=:rA|

APPARATUS FOR SUB-ZERO TREATMENT OF METALS Filed July 29, 1952 3 Sheets-Sheet .'5

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INVENTORS. BY mi? wmuwwn f/mw.

ATTORNEYS United States Patent APPARATUS FOR SUB-ZERO TREATMENT OF 1 METALS John K. Heyl and Wilbur H. Schweikert, Cincinnati, hio,

assignors to Super-Treat, Inc., Cincinnati, Ohio, a corporation of Ohio Application July 29, 1952, semi No. 301,43;

\ 4 claims. (ci. zzo-.36)

' This invention relates to a device for treating metals at sub-zero temperatures and is particularly directed to improvements upon apparatus of the type disclosed in Patent No."2,445,294, issued to A. L. Nelson.

There are many instances where it has been found useful toftreat metals at temperatures substantially below zero degrees Fahrenheit. For example, certain types of tool steels can be stress relieved at temperatures below minus 100 F. In fact, thereare many different types of steels whichV vexhibit extremely desirable metallurgical characteristics after they have been treated at reduced temperatures. Furthermore, it is often desirable to lower the temperature of metallic parts in order to shrink fit them. In such instances no metallurgical changes are sought, butrather two parts are firmly joined together by first thermally contracting one part and then allowing it tofexpand after it has been fitted together with its mating part. In other words, in a shrink fitting operation, one part which is to be fitted into or joined to another, is substantially chilled so that it contracts; and while this member is inthe contracted stage, the second member, which has been allowedto remain at a higher temperature is placed over the first member. As the temperature of thechilled member rises, it expands and eventually reaches a size sufcie'nt to prohibit disjointure of the assembled parts.

The present invention is concerned with devices for cooling metals inorder to accomplish these and other operations. Devices of this general type depend, for their cooling action, uponthe accelerated sublimation of Dry Ice which'is submerged in an organic solvent such as methanol. These two substances stabilize at a temperature approximately 110 F. lbelow zero, and as explained in the'Nelson patent, by drawing a vacuum on the surroundingfair their temperature may be stablized as low as "145" F. The methanol and Dry Ice are usually placed in a coolingfchamber or vat and the metals to be treated arelimmerse'd in this methanol carbon dioxide bath.

One ofthe principal advantages of using what might be termed a fchemical refrigerator, as comparedto a conventional mechanical refrigerator is that of economy. Aconve'ntional mechanical refrigerator requires almost ten'ho'urs to reach working temperature from room tem-v perature; Consequently, unlessit is in continuous use, a mechanical refrigerator is extremely uneconomical to operate since over long periods of time it is running unproductively, merely in order to lower its own temperature. Furthermore, its initial cost is considerably higher than that of a chemical refrigerator.

In contrast, by using Dry Ice and methanol as a refrigerant, the temperature of a cooling chamber can be reduced from room temperature to an operating temperature of from 130 to 140 F. in three hours. The coolingdevice can thus be used only when it is actually needed, since it is unnecessary to have it in operation for long precooling periods. This is not only economical but also extremely -convenient since the cooling apparatus can This disadvantage is the inherently limited range of temperature which can be maintained by means of a methanol Dry Ice cooling system. The equilibrium temperature of Dry Ice and methanol is in the vicinity of 112 F. at atmospheric pressure, and drops to minus 145 at 25 inches of vacuum. Thus the practical operating range of a chamber cooled by methanol and Dry Ice even with a variable vacuum pump system, would extend over only 35 F.

However, there are many metals which, if placed directly in a minus 140 F. bath, would be injured due to shock. ln order to treat these metals it is necessary to lower their temperature gradually in some predetermined manner. Furthermore, there are other metals at which optimum metallurgical properties can be reached by subjecting them to less severe temperatures of the order of -40 or -50 F. for example. This higher temperature range is also sufficient for many types of shrink fit work. Consequently it is desirable to extend the operating temperature range of a chemical refrigerator so that it may be used to treat ya larger group of metals, and economically perform a wider variety of functions.

One of the principal objects of the present invention is to provide a cooling device having at least one chamber in which the temperature may be accurately controlled over a wide range of temperatures varying approximately from minus 30 to minus 120 F. Generally it is the concept of this invention to provide a refrigerating device` may be maintained at a constant value of from minus F. to minus 145 F. This chamber will be termed the primary chamber and may be used for treating those metals which are best treated by direct quenching in an extremely cold bath.

The second chamber preferably contains methanol or some other heat transfer medium with a low freezing point and is kept at atmospheric pressure. It may be desirable, however, in some installations to merely have the second chamber filled with air rather than a liquid. Surrounding each of these chambers is a heat exchange jacket, in the preferred embodiment a coil of tubing. A heat transfer fluid, or coolant is circulated through the jacket surrounding the primary chamber, and then through the jacket surrounding the second chamber. This fluid is cooled by the primary chamber and in turn cools the secondary chamber before it is returned and recirculated through the primary jacket. The temperature of the secondary chamber can be accuratelycontrolled by regulating the rate of coolant flow. For, the more fluid which flows through the system, the more heat which will be removed'from the secondary chamber, thus resulting in kits being maintained at a lower temperature. In the preferred embodiment, a temperature responsive valve is provided for regulating the rate of coolant flow in response to the temperature of the secondary chamber.

A second object of this invention is to provide a cover for the primary chamber which can be readily removed. With the pressure in this chamber reduced to approximately minus 25 inches, the force required to lift the relatively large lid covering the chamber is very great, amounting to over two tons. This feature of the invention is predicated upon the concept of providing a two-part lid, one part of the lid constituting a c ap which fits over a` port ,Patented Apr. 17, 1956'V movingv the lid'into axclosedposition over the cooling :l0

chamb'enorinto a storage position in which it is entirely out .of .the way of anyone filling or emptyingwthe cooling chamber. The .lid positioning assemblyalso` provides a Y means for easilylifting the cap -and'li'd by a. partial turn Vofa handle.. The preferred embodiment of the lid. positionig assembly includes a vertical post which is pivotally. mounted .on..the.topY ofthe cabinet and supports an arm l Y whichverhangs the. lid. Suspended'frorn the arm is Va lifting member which is joinedtov the cap. A handle and eccentric linkage arrangement are also mounted on the arm in such' a wayV that rotationr of the handle reciprocates the lifting member and is Vthereby effective to raise the cap Vor force it in sealed engagement with the port. Furthermore, the main. lid portion is provided with a lip which overfts the cap so that after the caphas been lifted a smallV distance free of theport, it engages the lip and the main lid portion may be`raised. upon further'movement of the lifting member by rotation ofthe handle.

Hence, by means of the lid positioning assembly ofthe present invention, a lid may be moved from an out of the Way. position into a, position of registry with the top of a..co.olinguchamber. Then, by rotating a handle, it may belowered against the rim ofthe chamber and the cap pressedover the port to form. a seal for` thechamber,

lid'and also lifts Ythe entire lid, which may then be rotated 45 into 4an out of the wayposition while the. chamber is loaded and unloaded. Y

These and other objects and advantages of my invenf tion will ,be more clearly understoodfrom a consideration.. offthefollowing detailed description of the drawings.

In the drawings: Y

Figure 1 isa top plan view of a cooling apparatus constructed `in accordance withV the Ypresent invention..

Figure Z'is a frontA elevational 'view ofthe apparatus 55 shown in Figure 1.

Figure 3 Vis a side elevational'kview of the apparatusV shown in .Figure 1.

Figure 4 is a side view of the lid positioningassembly. Figurej is a top planfview of the lidliftingarm.

Figurel is an endview. of the lid lifting arm. Y '60 Figure. 7`is; an enlarged partial cross sectionalview of the lid'showing the capE and port construction. Y

Figure 8' is a diagrammatic view ofthe.cooling-systemL Y As shown inFig'ures 1, 2,and'3, thecoolingrdeviceofthe present invention includes .a cabinet llhaving a pri-` 5 mary chamber 11 and a secondary chamber V12.-

Primarychamber 11`is filled With.D`ry Iceimrnersedv in methanol ora similar organic solvent suchas vamyl chlorride, propylv ether, or the like. This solution supplies thecooling action for the entire apparatus.. A perforated 70 liner'13 is'placed'inthe-'bottom of vcylinder 11; and'an annular-space 142 isr thus formedL between'they liner -andV thelwalltof-'cylinder'15 Primary' coi1s16 are placedr Withinf-theannulrfspaceand are connected byy pipe--17VV n toaset of coils .tiare'sidingin the4 annular spaceformed between cylinder 20 and perforated liner 21 of secondary chamberlZ. Coil 1Sis returnedithrough"line22'to"reser= voir 23 which is, in turn, connected with pump 24, from which line 25 leads to the primary coil 16. These coils Y and their associated piping and pump comprise the coolant system for cooling the secondary chamber 12.

To evacuate primary chamber 11, a vacuum pump 26 is provided, .although any other.-suitable'meansntevacuating the chamber may beemployed. Vacuum pump 26 is driven by motor.27 through coupling 28.and1.includes. intake filter 30 (Figures 3 and. 8). Suction line. 31of pump 26 is connected to T 32. From. T 32, line133 leads to gauge 34, and line communicates with chamber 11.

To control the temperaturev in thesecondary chamber 12, a temperature responsive apparatus, indicated at 36 in Figure 8, is connected to a bulb 37 disposed within the secondary tank. Thetemperature.responsive devicepreferably includesV a recordinggaugeA 4l).a.nd..controls.the v temperature. in chamber, 12'. by regulating the, ow.. of.. coolant throughV the coolantfsystem, including, coils,..16.:f and 18. Control of coolant ow may be. exercisedin As shown diagrammatically in Figure,VV the@ temperature responsive device-may controla` valve 41. which is etective to channel the. output of. pump 2.4 through primary coil 16 ,and` secondarycoil 18; orto recir.- culate the coolantthrough; line. 42, back. to reservoir-.23- Without passingthrough coils 16and 18.4

Alternatively, the..temperature. responsive device, could controlthe operation of motor 43. kwhich drives .,pump, 2.4-I so that the motor is .operative only when'1 the temperature:-i in secondary chamber.12..is.equal.to.or above thecdesireclNA temperature. To alter, the. temperature maintainedl in the secondary chamber,- it is .onlynecessary to. adiust temwhichmay then `be evacuated. When it is desired to reo perature responsive device 36 soA that it will vactuate .valve 41 or motor 43 at different temperatures.

The action. ofthe. sublimationof the-*DryI Ice-.thither methanol contained. `in chamber. 11. is. vsuflcient. to cause. an. active. circulation. of, thev methanol. aboutythe which..a1' ev placed .within thechamber. However, secondeary chamberlzcontainsionly acoolant and .nosuclr actirn. is available tocausecirculation.: Therefo1'.e;in.order.to7 more effectively cool the metal parts placed within chambery. an agitator pump..44 drivenby motor. 45;',is provided. ThispumpiiscOnneCtedtct.seeondanychamherv 12,.through.pipes 46 and47, and.effectivelycirculates-the.. liquid containedinthat chamber. j

Primary chamber 11 -is.p rovided .withaa lid 48 .forrsealf ingltthe.. chamber tor-permit itsevacuation., Secondary 0 chamber 12.is provided with alid 49 -which .servest-ornllyfJ to, reduce. heat lossfrom the chamber, since the-chamber: isA not evacuatedand therefore does not requirezamairf tight seal. Asbest shown in,.VFigur.es-4vand;7, lid 48 .'in;

cludes a mainlidportion 50.having-:upper,andlowerplates. 51 and. 52., These plates are.separated by ringe-53.*.prof` viding..an.insulating air spacef54iwithinftheflid. The

lid isprovided. with acentral port 55.irr;whicl1fbushing. 56, constructed. of an insulating,materialasuch asformica,

is inserted. Bushing.includesaange 57 whichcomfpressesgasket 'iagainstlower plate 52 toprovideeanair-f Y tight sealbetween .p ort wall 59 and :bushings-5.6: Bearing,

ring 60. overts the top. .ofbushiriglandtmay becemented. or otherwise. secured. toi the. bushingito --holdaitf ini-place: withintheport. A- lip, memberv 6.1.-istseeured.bymeans.- of bolts62.;to ring-63;V disposed .on the.-inside ofthe-,upper plate 51. Lip 61 is contiguratedftozgformventholes 641 and. has a ,f central opening 65 which accommodates-part of capr66., n

The function of cap .,66 is. to..close.port. .whenathevprimary, chamberI isA evacuated.` When removingrhe. lidcap 66 is' trstlifted'fron the port vto release the ,vacuum within the chamber before the main, lidpprtionS' is 'liftedi Cap' 66 is tted withfa sealing gasket 67 which resides-in anannular groovein-thecapandnisdisposed" for-fengagement 'with-bearingring 6013 inverte'dicupv mary chamber.

68 `or 'similargmeans such as fingers, is welded to the top of cap 66 and is provided with an opening 69 for receivingzrod 70 which includes a head 71 or other enlargement at its end. yRod 70 is threaded into tube 72 and together with pin 73 they constitute lifting member 74. 1

I'l'le lid positioning assembly 75, of which the lid lifting member 74 is one component, includes a verticallyvdisposed rotatable'post 76. Arm 77 extends horizontally outwardly from the post over the lid 48. Arm 77 is of generally rectangular cross section and is welded orvotherwise secured to post 76. A boss 79 is provided 'on the'lower edge of the arm for guiding lifting member474. 'Ai llet plate 78 and stiffening ribs 80 strengthen thejarm; The" arm carries an eccentric lever arrangemeritA 81 including'link `82 which is hngedly connected to the arm as at 83. 'Ihe other end of link 82 is provided with a groove 84 for slidably receiving pin 85 of eccentric plate 86. Plate 86 is rigidly mounted upon shaft 87 which is journaled in block 88, secured to arm 77. Shaft 87 can be rotated by handle 90 which is joined thereto,

rotation of the handle being limited by stops 91 and 92 which are secured to arm 77. Link 82 is providedv with a second longitudinal slot 93 which accommodates pin 73 of lifting member 74, ylink 82 fitting in recessed porton 95 of tube 72. Y

When operating the chilling apparatus, methanol and Dry Ice are placed in primary chamber 11. Arm 77 is then rotated so that lid 48 covers the top of the pri- The handle 90 is then rotated in a clockwise direction rotating eccentric plate 86 in the same direction so that pin 8S forces link 82 downwardly.

Link 82 contacts pin 73 forcing the lifting member downwardly. The lifting member in turn urges cap 66 against bearing ring 60 to seal port 55. `Vacuum pump 26 is then started to draw a vacuum on chamber 11. Also if the secondary chamber is to be used, the desired temperature is set on the temperature control device, and pump 24 is started to circulate the coolantV through the primary and secondary jackets.

After the temperature of the primary chamber is stabilized handle 90 is rotated counterclockwise rotating eccentric plate 86 so that pin 85 forces link 82 upwardly causing lifting member 74 to engage cup 68, thereby raising cap 66. This opens port 55 and releases the vacuum within the primary chamber. Further counterclockwise rotation of the handle causes lifting member 74 to be raised an additional amount, where- .upon cap 66 engages lip 61 raising the entire lid. The

lid may then be rotated into the storage position by turning post 76. After the primary chamber has been filled with the material to be chilled, the lid is again placed over the chamber and the vacuum restored.

The secondary chamber may be used as soon as its temperature has stabilized, which will normally occur prior to the stabilization of the primary chamber temperature. The control over the temperature of the secondary chamber is exercised by temperature control device 36 which, by governing the circulation of coolant through valve 41 or pump 24, regulates the temperature of the secondary chamber accurately irrespective of the temperature of the primary chamber.

It will be noted lthat in the embodiment shown, coils 16 and 18 of the coolant system are completely immersed in the liquids contained in the primary and secondary cooling chambers. Thus, the heat losses involved in cooling the secondary chamber by means of a circulating coolant uid are minimized, and furtherv more the coolant fluid is maintained at the lowest possible temperature thereby minimizing the time required to lower the temperature of the secondary chamber and in fact permitting its temperature to stabilize before the primary chamber reaches its equilibrium temperature.

While this invention has been disclosed principally in connection with a device for chilling metals, it will be obvious that its utility is not. limited solely to this application." Rather-,the Tcooling device disclosed herein may be employed advantageously in any eld where chamber, and a lid positioning. assembly, said lid be-v Y ing constituted by `a mainlid portion adapted for engagement with the top ofsaid chamber and being configurated to have a port therein, a cap disposed above said port and being adapted for vertical movement into and out 'of sealed engagement with said port, and la lip secured to said main lid portion and disposed to engage said cap upon Yupward vertical movement, thereof, said lid positioning assembly comprising an arm extending horizontally over said lid, a lifting member in cooperative engagement with said cap, means carried by said arm for reciprocally moving said lifting member vertically, whereby upon upward movement of said member said cap is initially disengaged from said port releasing the vacuum Within said chamber, and upon further movement of said lifting member, the cap is brought into engagement with said lip, whereuponV still further movement of the lifting member results in the main lid portion being raised.

2. A lid for sealing the top of a vacuum cooling chamber, a lid positioning assembly, said lid being constituted by a main lid portion adapted for engagement with the top of said chamber and being confgurated to have a central port therein, a cap disposed above said port and being adapted for vertical movement into and out of sealed engagement with said port, and a lip secured to said main lid portion and disposed to engage said cap upon upward vertical movement thereof, said lid positioning assembly comprising an arm extending horizontally over said lid, a lifting member depending from said arm and in cooperative engagement with .said cap, an eccentric `lever arrangement carried by said arm for reciprocally moving said lifting member vertically whereby upon upward movement of said member said cap is in itially disengaged from said port releasing the vacuum within said chamber and upon further movement of said lifting member the cap is brought into engagement with said lip whereby upon further upward movement of said lifting member the main lid portion is raised. A

3. A lid for sealing the top of a vacuum cooling chamber mounted within a cabinet, a lid positioning assembly for moving said lid into a storage position or into a position in which it seals said cooling chamber, said lid being constituted by a main lid portion adapted for engagement with the top of said chamber and being congurated to have a central port therein, a cap disposed above said port and being adapted for vertical movement into and out of sealed engagement with said port, and a lip secured to said main lid portion and disposed for engagement with said cap upon upward movement thereof, said lid positioning assembly comprising a vertical post rotatably supported by said cabinet, an arm mounted upon said post and extending horizontally over said lid, alifting Vmember in cooperative engagement with said cap, means carried by saidy arm for reciprocally moving said lifting member vertically, said means being actuated vby a handle in such a manner that initial rotation of said handle results in upward movement of said lifting member and said cap releasing the vacuumwithin lsaid chamber, and further movement of said handle results in the lid portion being raised.

4. A lid for sealing the top of a vacuum cooling chamber, a lid positioning assembly for moving said lid into a storage position or into a position in which it seals said cooling chamber, said lid being constituted by a main lid portion adapted for engagement `with the top of said chamber and beingconigurated to have a central port thereimxcap:.disposedahovegsaidtpnrtxandbeingsadaptedz; for; yvertical movementiintozandenntzof-sealed; engagement:

and disposedffor;engagemenizwithzsaidszcap;.upon upward.Y

movement `thereo` said lid; positioning;- assemblyy com;-

prising a vertical post, an arm mounted uponasaidpostV and extending horizontallvysover-saictlid, azlifting member in: cooperativefengagemenbwithgsaidcap, means carried by. said armonfreciprocally :moving said ylifting member'. vertically, saidzmeanslincludingfadever hingedLy-mountecb 10i upon. said arm,.said=.1ever beingacongurated toiformY a rst; slot; and a seeondpslottherein; .a shaft,4 anv eccentric:

Y block mountedvuponsaid -sli'aftrfsaid :block :carrying azpin,

saidxpin engagingfzsaidzfrstzslot:in:;said;1ever, saidlifting..A

melnbenhayingga removed portionnto accommodatezsaid leven.' andaa; pim disposed; within.` said-second;v slot imsaid 1ever,; al. handle-f.l secured torsvsaidzshait'Y whereby rotation ofiAV said handle causesffsad:4 levenv tcm itotateeY raising-.1, saidl' liftngmemberfand saidLcapzand; further..l rotation: of 'said handlefcausessaid main portiomofithedid'to-beflifted;

Referencested' in thezflie ofxthis :patent- UNITED STATES PATENTS Shoemann V Apr. 1 

1. A LID FOR SEALING THE TOP OF A VACUUM COOLING CHAMBER, AND A LID POSITIONING ASSEMBLY, SAID LID BEING CONSTITUTED BY A MAIN LID PORTION ADAPTED FOR ENGAGEMENT WITH THE TOP OF SAID CHAMBER AND BEING CONFIGURATED TO HAVE A PORT THEREIN, A CAP DISPOSED ABOVE SAID PORT AND BEING ADAPTED FOR VERTICAL MOVEMENT INTO AND OUT OF SEALED ENGAGEMENT WITH SAID PORT, AND A LIP SECURED TO SAID MAIN LID PORTION AND DISPOSED TO ENGAGE SAID CAP UPON UPWARD VERTICAL MOVEMENT, THEREOF, SAID LID POSITIONING ASSEMBLY COMPRISING AN ARM EXTENDING HORIZONTALLY OVER SAID LID, A LIFTING MEMBER IN COOPERATIVE ENGAGEMENT WITH SAID CAP, MEANS CARRIED BY SAID ARM FOR RECIPROCALLY MOVING SAID LIFTING MEMBER VERTICALLY, WHEREBY UPON UPWARD MOVEMENT OF SAID MEMBER SAID CAP IS INITIALLY DISENGAGED FROM SAID PORT RELEASING THE VACCUM WITHIN SAID CHAMBER, AND UPON FURTHER MOVEMENT OF SAID LIFTING MEMBER, THE CAP IS BROUGHT INTO ENGAGEMENT WITH SAID LIP, WHEREUPON STILL FURTHER MOVEMENT OF THE LIFTING MEMBER RESULTS IN THE MAIN LID PORTION BEING RAISED. 